1. Field of the Invention
This invention relates in general to seed density monitors and counters employed in seed planters and, more particularly, to an improved seed sensor for use therewith.
2. Description of the Prior Art
As is well-known in the art, a seed planter typically includes a group of seed chutes, one for each row, which automatically dispense individual seeds from hoppers into furrows formed in the ground by the planter as it is moved across a field. Seed planter monitors such as those disclosed in Gregory U.S. Pat. No. 3,422,776, issued Jan. 21, 1969, and Steffen U.S. Pat No. 3,912,121, issued Oct. 14, 1975, are operable to monitor and count the number of seeds periodically dispensed by seed planters. Such seed planter monitors employ electronic counting devices which receive electrical seed counting pulses from seed sensors located in the seed dispensing chutes.
Prior known seed sensors include electronic pulse-generating circuitry typically actuated by the output of relatively slow-reacting photo-conductive cells. However, as those fimiliar with the art will readily appreciate, a problem has arisen with the use of photo-conductive cells in seed sensors. When multiple seeds in close or partially overlapping relationship drop past a slow-acting photo-conductive cell, the sensor frequently counts the multiple seeds as one, with resultant inaccuracy in the electronic pulse information supplied by the sensor to the monitoring circuitry.